Manufacture of alkyl compounds



' methods hitherto 80" mary alcoho Patented Feb. 19, 1924.

1,43 ,2 9 UNITED STATES PATENT OFFICE.-

WALTER BADEB, OF SPONDON, NEAR DERBY, ENGLAND, ASIGNOR TO DB. HENRY I DBEYFUS, OF LONDON, ENGLAND.

4 MANUFACTURE OF ALKYL COMPOU'NI DS.

1C0 Drawing.

7 '0 all whom it may concern Be it known that I, WALTER BADER, a citizen of the Swiss Republic, of Spondon, near Derby, England, have invented certain I new and useful Im rovements in or Relating to the Mann acture of Alkyl Coinpounds, of which the following is a specification.

vOf the neutral sulphates of primary al- 10 kyls only dimethyl sulphate has attained technical importance as an alkylating, agent, because it is the only one that can e prepared on a a large scale with an econom1cal yield. The hig known for the preparation of neutral sulphates yield large amounts'of undesirable by-products, especially hydrocarbons of the ethylene type. This invention relates to a process of manufacturing neutral. alkyl sulphates which gives economical yields not only in small experiments but also on a lar e scale.

It is particularly suitable for diet yl sulwhich has not yet been prepared -in-' ghate, 26 ustrially in a satisfactory manner.

It has been proposed to pre are alkyl hydrogen sulphates, especially at yl hydroen sulphate, in a practically pure state by V istilling sul s, e.'g. ethyl alcohol, at very low temperature, and then to convert them by disti lation under reduced pressure into neutral a l sulphates. For diethyl 'sulphate a yie d of of the theory is said 85 to be the hi hest obtainable by this method. The disti lation of a large quantity of ethyl hydro en sulphate, even in a quickworking 'stil, necessarily takes a considerable time. During this time those molecules 40 of ethyl h drogen sulphate that have not yet been ecomposed are under the influence of high tem erature, the consequence being that not on y the reaction-" occurs, but a number of side-reactions,

the smallipartof the. iq

' products of the disti er alkyls treated by the hur trioxide into absolute pri-,

Application filed October is, 1921. semi-no. 507,577. I

distillation of alkyl hydrogen sulphates or of mixturesflcoiitaming alk l h drogen sulphates is efi'ected underredl iced pressure in such a way that :at an given, moment only uid which is actually undergoin distillation is under the influence of'the eat.

Further-accordingl to the invention the ation, i. e. vapours and residue .ar'e: uickly and continuously removed from t e point where distillation occurs, and'.,from contact with the distilling qThe invention comprises further features hereinafter appearing.

In-carryi 'gtout-the invention, the liquid to be-..dis'til' ad is introduced either in small portions or continuously, into the heate'd-z'oneof a vacuum still which allows an instantaneous withdrawal of the vapours towards a condenser, and the continuous removal of the residue, so that it does notcoin'e in 'con act with the inflowing fresh liquid. 1 I

F The invention is not concerned with any particular type of still. The liquid to be istilled may 'for. instance be led to. run, as a thin'film over a heated surface, or it may be de osited on a revolving drum or a travcling and which brings it in the hot zone of t ejstill,'or it may ow-in a'thin stream through a heated coil or down the interior of a heated revolving tube, or it may enter the still in the form of a spray, andso forth.

The liquid containing al 1 hydrogen sulphate may be 'prepared y several well nown methods which do not form part of this invention.

It is indeed indifferent whether the liquid has been obtained by mixing a primary alcohol with sulphur trioxide or with fuming or ordinary sul huric acid, or by absorbing an ethylenic' ydrocarbon or an alkyl oxide insulphuricacid, or byv decomposing a salt of an alkyl sulphuric acid (e. g. ethyl sodium sulphate obtained as a by-product in using diethyl sulphate as an ethylating agent) by a strong mineral acid. In all these cases'a solution results which is.

either substantially alkyl hydrogen sulphate or contains besides more or less sulp uric acid, free alcohol, water, ether etc. All these li uids yield dialkyl sulphate when treated y my method, but I prefer to use gradually,

of 5 mm. mercury. At the bottom of the :pears as a se arate la er. consisting su stantial y of ethyl hydrogen a mixtiire of alkyl hydrogen sulphate and the corresponding alcohol only, contamin very little free sulphuric aci water an other bodies. Such a mixture may for nstance be prepared from sulphurtrioxide and a large excess of a primary alcohol.

The following example is iven as an explanation, but the invention is not confined to this particular way of execution.

Ewample.

The still is a vertical tube heated electrically or otherwise. The liquid to be dis? tilled flows in at the top through a small revolving orifice which deposits lt-regularly all round on the inner surface of the tube, so that it flows downward as a thin film.

A high vacuum is maintained in the tube still there collects sulphuric acid and some tarry matter, while the distillate consists principally of diethyl sul hate, some ethyl hydrogen sulphate, free a cohol and a litt e water. The yield of diethyl sulphate is higher than the ethyl hydrogen sulphate present in the original liquid can explain, e. g. 110% or more of the theoretical yield calculated on the ethyl hydro en sulphate originally present. The fol owing equations are suggested as an explanation of this fact,-

according to which it would appear that the sulphuric acid liberated in the reaction combines immediately with the free alcohol present in the solution.

If the original liquor contains a considerable amount of free sulphuric acid, which is the case if it has been prepared with ordinary sulphuric acid, or with fuming acid of low anhydride content, a larger excess of free alcohol than indicated in-the example is used with advantage.

In the distillate the diethyl sulphate ap- The otherv layer,

sulphate and alcohol can simply be mixed with the li nor for a next operation. In this way a the alcohol used in excess re= neutral alkyl sulfate,

be kept taining free alkyl hydrogen su .tion quickly and continuously from and from contact with the incense turns into the process. .The distillates may however be worked up in any other con- .venient wa for the recovery of alcohol.

Other a kyl sul hates are prepared in a similar way by su stituting meth l, prop l, butyl, etc. alcohol for ethyl alco 01 in t e example above.

What I claim and desire to 'secure by Letters Patent is a 11 In a process for the manufacture of subjecting liquid containing free alkyl hydrogen sulfate to distillation under reduced pressure in a man ner whereby at any given moment only that small part of the liquid which is actually undergoing distillation is under the influence of heat, and removing the products of distillation quickly and continuously from the distillation point and from contact with the distilling liquid.

2. In a process for the manufacture of neutral alkyl sulfate, subjectin liquid con- Ffate and the corresponding alkyl alcohol to distillation under reduced pressure in a manner whereby at any given moment only that small part of the liquid which is actually undergoing distillation is under the influence of heat, and removing the products of distillathe distillation point distilling liquid. 3. In a process neutral alkyl sulfate,

'for the manufacture of subjecting liquid containirig free alkyl hydrogen sulfate and a considerable amount of the corresponding alkyl alcohol in an uncombined state, to distillation under reduced pressure, in a manner whereby at any given moment only that small part of the liquid which is actually undergoing distillation is under the influence of heat, and removing the products of distillation quickly and continuously from the distillation point and from contact with the distilling liquid.

manufacture of 4. In a process for the a liquid neutral alkyl sulfate, subjectin consisting essentially of free alky sulfate and the corresponding alkyl alcohol only, to distillation under reduced pressure, in a manner whereby at any given moment only thatfism'all actually undergoing distillation is under the influence of heat, and removing the products of distillation quickly and continuously from the distillation point and from contact with the distilling liquid.

5. In a recess for the manufacture of diethyl sul ate, subjectin liquid ,containing free ethyl hydrogen sul ate to distillation under reduced pressure in a manner whereby at any given roe hydrogen part of the liquid which" is I moment only that small part of the li uid which is actuatually undergo--- ation is under the influence of ing disti removing the products of distillaheat, and

diethyl sul ate, sub'ectin tion quickly and continuously from the distillation point and from contact with the distilling liqud.

6. In. a process for the manufacture of diethyl sulfate, subjecting liquid containing free eth 1 hydrogen sulfate-and ethyl alcohol to distillation under reduced pressure in a manner whereby at any given moment only that small part of the liquid which is actua ly undergoing distillation is under the influence of heat, and removing the products of distillation uickly and continuously from the distillation point and from contact with the distilling liquid.

7. In a rocess for the manufacture of diethyl sul ate, subjecting liquid containing free ethyl hydrogen sulfate and a considerable amount of ethyl alcohol in an uncombined state, to distillation under reduced pressure in a manner whereby at any given moment'only thatsmall part of the liquid which is actually under oing distillation is under the influence of cat, and removing the products of distillation quickly and continuously from the distilling point and from contact with the distilling liquid.

8. In a rocess for the manufacture of a liquid consisting essentially of res et yl hydrogen sulfate and ethyl alcohol only, to distillation under reduced pressure in a manner where by at an given moment only that small part of t e iquid which is actually undergoing distillation is under the influence of eat, and removing the products of distillation quickly and continuously from the distillation point and from contact with the distilling liquid.

9. In a rocess for the manufacture of diethyl sullhte, subjecting a liquid containing about 65 per cent of free ethyl hydrogen sulfate and about 30 per cent of free ethyl alcohol to distillation under reduced I under reduced pressure in a manner where-' by at any given moment only that small part of the liquid which is actually undergoing distillation is under the influence of heat, and removing the. products of distillation quickly-and continuously from the distillation int and from contact with the distillinlg iquid.

n testimony whereof I have hereunto subscribed my. name.

WALTER BADER. 

